The present invention relates to an object orienting machine, particularly caps or capsules, provided with an improved object selection function.
Machines for orienting objects are known, in which the objects are received in bulk in a hopper from which they are withdrawn and fed to a device configured to orient the exiting objects all in the same manner.
Such known machines are widely used, for example, for orienting caps, such as plastic caps, crown caps, and the like, in bottling lines.
The known devices for orienting caps comprise a belt conveyor with small planar blades, oriented perpendicularly to the surface of the same belt, passing through the hopper containing the objects to be oriented and afterwards it follows a substantially vertical ascending path. The objects are withdrawn from the hopper by virtue of the perpendicular small blades and, in the ascending length of the belt conveyor, the objects remain rested on the small blades, acting as support bases. The arrangement of the belt conveyor and the dimensions of the small blades are selected so that only the properly oriented objects (i.e., in the preset manner) maintain a stable balance on the small blades and continue the ascending path on the belt conveyor, while the improperly oriented objects (i.e., not in the preset manner) fall back to the hopper beneath.
In such a manner, at the end of the ascending length of the belt conveyor, only the properly oriented objects are still present on the belt.
At this point, the properly oriented objects are withdrawn from the belt conveyor and directed towards the successive stations of the manufacturing line, for example, towards a bottling station in the case where said objects are caps.
Machines for orienting objects of the type described above are known, for example, from the documents WO 2006/045927, U.S. Pat. No. 5,394,972, U.S. Pat. No. 5,586,637 and EP2196417.
In some of the known devices, the withdrawal of the objects at the end of the ascending length of the belt conveyor occurs by virtue of the use of a pneumatic system, which allows generating a fluid jet (for example, air) under pressure to push the objects laterally out of the belt conveyor, towards conveying means to the successive station of the manufacturing line.
In other known devices, the withdrawal of the objects occurs by falling, i.e., under the action of the force of gravity in a zone behind the ascending side of the bladed belt conveyor.
However, the object orienting efficiency by gravitational selection by an ascending bladed belt is very sensitive to the shape of the object to be oriented. In fact, such technology is indicated only for capsules or caps with a diameter that is larger than their height, for example with a ratio Ø:H=2:1. (The cap could have a diameter of 30 mm and a height of 15 mm), because in this case the object barycenter is very near to the ascending belt plane, stabilizing the position of the rested objects having the desired orientation both during the selection step and during the withdrawal of the objects from the belt.
The orientation of “tall” caps, i.e., with a height that is higher than their diameter, by a gravitational selection with a bladed belt would require an enlargement of the planar small blade so as to obtain again the desired relative positioning between the object barycenter, the ascending plane of the belt, and the resting plane of the small blade (as shown in the FIGS. 1 and 2).
However, due to the intrinsic instability of the “tall” caps in a dynamic system, the “tall” cap tends to roll and rotate on the small blade, as shown in FIG. 3, and it would remain in any case rested on the enlarged small blade. This results in a mispositioning of the single rotated cap and the risk of a domino effect on the adjacent caps rested on the same small blade, thus amplifying the phenomenon up to the arrest of the system.
This prevents even now the use on an industrial scale of the gravitational selection by means of a bladed belt for “tall” caps.